1. Field of the Invention
The invention relates to an apparatus for winding a material web, in particular a paper or board web, onto a spool, in which the material web is led over a carrier drum and a winding nip is formed between the spool or the reel to be formed on the latter and the carrier drum. The spool is guided by primary arms in a primary winding phase and is capable of being pressed onto the carrier drum by pressing levers provided on the primary arms. While in a secondary winding phase, it can be pressed onto the carrier drum by secondary arms.
2. Description of the Prior Art
Winding apparatus of this type is disclosed, for example, in documents DE 35 39 980 C2, EP 0 561 128 B1, DE 198 22 261 A1 and WO 98/52858.
The previously common, so-called horizontal winders for standard applications, having a spool guided horizontally in the secondary winding phase and without a center drive in the primary and secondary range, essentially have the following features: A stationary carrier drum is driven at a drive-side journal. The composition of the carrier drum surface depends on the requirements of the various paper grades and winding parameters. For specific uses, rubber-covered carrier drums are used. These have to be removed and reground at time intervals of about 7 to 12 months. The primary arms are mounted, in particular, eccentrically, on the bearing housings of the carrier drum. The line force required for the winding operation between carrier drum and spool is produced in the primary range by the additional pressure which is effected by pressing levers provided on the primary arms and which, in particular, can be actuated by hydraulic cylinders. The line force produced by the inherent weight of the empty spool is normally compensated for by load-relieving cylinders. In the secondary range, the line force is produced by the so-called secondary arms. These arms, in particular, again actuated by means of hydraulic cylinders, accept the spool after it has been deposited on the running rails by the primary arms, and press it against the carrier drum until the maximum roll diameter is reached. In order to produce a high-quality reel, the line force must follow a predefined intended profile over the entire reel build-up, that is to say both in the primary and in the secondary range. The necessary hydraulic pressures in the pressing cylinders of the primary and secondary pressing system and in the load-relieving cylinders are calculated while taking account of the geometry and of the inherent weight components (spool position, force action directions of the pressing levers, inherent weights).
Such a conventional horizontal winder has, inter alia, the disadvantage that, in order to remove the carrier drum, the primary arms have to be separated from all the connections (pivoting cylinders, parallel guide, electrical and hydraulic connections, and so on) and also have to be removed.
In addition, in the case of the conventional horizontal winder, there is a lack of direct line force measurement. The line force actually acting between spool and carrier drum is distorted by frictional forces in the hydraulic cylinders, and in the lever and cylinder pivots. The frictional forces are not constant. They can change over the running time and, moreover, lead to skewed line force profiles. Faults are generally detected only through winding faults. A particularly critical point is the transfer of the spool from the primary to the secondary winding system, in which both pressing systems are effective for a short time. In this case, a line force increase (peak) is unavoidable. This can result in the reel produced in the primary range being damaged by the briefly higher line force. A further distortion of the line force in the secondary range can result from any equipment which may be present for vibration damping (friction brake on the secondary arm). In this case, it has already been proposed to incorporate force measuring pins in the pressure rollers of the secondary arms, with which the pressing forces on the secondary arm can be measured directly. However, because of the pressing geometry which changes over the winding profile, it is necessary for the measured signal to be converted as a function of the position of the primary arms. At least for the profile of the line force in the primary range, this proposal does not provide any advantages.